\begin{tikzpicture}

\definecolor{darkgray176}{RGB}{176,176,176}

\begin{axis}[
tick align=outside,
tick pos=left,
x grid style={darkgray176},
xmin=0.9, xmax=3.1,
xtick style={color=black},
y grid style={darkgray176},
ymin=0.7, ymax=7.3,
ytick style={color=black}
]
\addplot [
  draw=black,
  mark=o,
  only marks,
  scatter,
  scatter/@pre marker code/.append style={/tikz/mark size=\perpointmarksize},
  visualization depends on={\thisrow{sizedata} \as\perpointmarksize}
]
table{%
x  y  sizedata
1 5 9.772050238058398
2 7 9.772050238058398
3 1 9.772050238058398
};
\end{axis}

\end{tikzpicture}
